Eight severity levels, used by four people with four different interpretations, producing a log where error meant nothing in particular.
| level | means | wakes somebody |
|----------|--------------------------------|----------------|
| critical | the service cannot serve | yes |
| error | one operation failed and a | no |
| | human must eventually act | |
| warning | recovered, or degraded | no |
| info | a business event worth keeping | no |
| debug | development only, 7-day | no |
| | retention | |The column that resolved the arguments is the last one: whether a level wakes somebody is a concrete question with a concrete answer, and everything else follows from it. Three of the eight PSR-3 levels are unused here by agreement, which is fine — a level nobody can define is worse than a level nobody uses.